Diagnostic Tests During Pregnancy : An Overview

7 min read

Written by Editorial Team

Editorial Team

With a rich experience in pregnancy and parenting, our team of experts create insightful, well-curated, and easy-to-read content for our to-be-parents and parents at all stages of parenting.

Diagnostic Tests During PregnancyDuring the nine months of pregnancy, a woman has to go through many scans and tests to ensure the proper growth of her baby. Yes, we are talking about diagnostic tests during pregnancy. These diagnostics can make her feel as she has spent most of the time in doctors’ clinics only. But these tests, scans, and regular checkups are very essential.

It does serve a very important role in spotting, ensuring, and preventing any complications during pregnancy so that you and your baby can remain healthier in the long run. So the question is what do you mean by diagnostic tests and how many tests needs during the whole period of pregnancy?

In This Article

What Are Diagnostic Tests During Pregnancy?

Diagnostic tests are simple medical tests that help to find any health risk that could affect you or your baby during the nine months of pregnancy. These tests help to diagnose or detect any underlying disease. They can also subclassify the disease in terms of severity.

Few conditions that can be detected with the help of diagnostic tests are HIV, Diabetes, Down’s syndrome, anemia, or any other physical abnormalities. Usually, a diagnostic test during pregnancy involves an ultrasound, blood test, and urine test.

What Are The Benefits Of Diagnostic Tests In Pregnancy?

Diagnostic tests ensure the early detection of any potential health risk during pregnancy and can help mothers to make well-informed decisions about their health. These tests are effective in detecting abnormalities like certain hereditary or spontaneous genetic disorders.

For example, an ultrasound can detect your baby’s growth or any physical abnormality like spina bifida, it will also inform you whether you’re having twins or not, whether your pregnancy is ectopic pregnancy or a normal one. They can help you and your doctor in deciding the correct treatment during or after your pregnancy.

Which Diagnostic Tests Are Done During Pregnancy?

For a healthy pregnancy, the doctor performs many tests and scans for nine months. Here we will take you through each one and will try to explain their importance in pregnant women’s life.

Blood-Related Diagnostic Tests

What Are The Benefits Of Diagnostic Tests In Pregnancy_

These tests usually involve a blood sample taken from the pregnant mother. Doctors generally advise most of the blood tests in the first trimester usually during their first visit. But these tests perform any time whenever they feel it’s required, most likely in the last trimester.

Some of the blood tests are:

1. RH test

During your first trimester, the doctor will check your blood to confirm the blood group and also to know whether it’s Rh –negative or positive. If it turns out that you are Rh-positive, then an injection is known as Anti- D will be given once during the pregnancy and other after childbirth only if your baby is Rh-positive. Anti-D will protect you from developing antibodies that could be dangerous during this pregnancy or in future pregnancies

2. Complete Blood Count (CBC)

A CBC test is done to know your hemoglobin range. If it’s less, then the doctor can recommend you some iron supplements and can guide you about iron-rich food. The test also informs us about our platelets and white blood cell count – an elevated range will indicate an infection

3. HIV Test

The HIV test is a must-to-have test for a pregnant woman. If your result is positive for HIV then medications will be given to you in order to prevent the spread of virus to your unborn baby. In addition, your doctor can advise you to start thinking about C-section as it can prevent spreading the infection

4. TSH Test

This test detects the amounts of TSH in the blood. Below-normal levels of TSH indicate hyperthyroidism and is treated with anti-thyroid medications

5. T3 and T4 Test

If TSH levels are low, another blood test is performed to measure T3 and T4. Elevated levels of free T4 confirm the diagnosis of hyperthyroidism. Read more about Hypothyroidism in pregnancy here

6. Rubella Titter Test

It is done to check the immunity of pregnant women to the rubella virus. Most women are immune to rubella, either because they’ve been vaccinated or had the disease as a child. But if in case you are not immune or your test result showed you are vulnerable to it then it’s very important to avoid anyone who has the infection or has traveled to any such country where the disease is still prevalent

7. Blood Sugar

A blood sugar test is done to check the women’s sugar levels and also to determine the chances to develop any diabetes in future months of pregnancy. If in case this test shows higher levels, then an immediate change of diet plan or medications are given to the women

8. QUAD or Triple Marker Test

The quad test is usually done between 15 to 20 weeks and is also referred to as multiple marker, AFP4 or quadruple test. This test is very useful in the detection of chromosomal abnormalities like trisomy 18 and Down syndrome. It can also detect neural tube defects, such as spina bifida.

The positive result of the test will suggest a higher risk and the chance that your baby will have a birth defect and a negative or normal result means that your baby probably doesn’t have a birth defect. But it doesn’t guarantee that you will have a normal baby

Urine Related Diagnostics Tests

Urine tests

Along with the blood tests your doctor will also recommend you to go for a urine test, which means you have to give them a sample of your urine. Most doctors perform these tests one time during the pregnancy. However, doctors repeat it in case any symptom of urine infection appears at any time during the nine months.

Urine Tests During First Trimester

The urine test is very important in the first trimester because urine infections if not screened and treated timely can cause serious problems to you and your baby. Simultaneously, it can also detect the presence of traces of blood, sugar, or protein.

Ultrasound Scans in Pregnancy

Ultrasound Scans in Pregnancy

Ultrasound scans are safe, non-invasive, and a very useful diagnostic tool for screening some birth defects (for example NTD defects). They can also detect an ectopic pregnancy, can assess fetal growth and the risk of Down syndrome. They can also help you with checking fetal heartbeat.  This gives you an estimated date of delivery.

This is especially reliable if in case you have no idea when your last period was. It can inform you if in case you are pregnant with twins. Mostly, doctors perform one in each of the trimesters to check the progress of your fetus.

However, sometimes you might have to do extra scans. Doctors prescribe this if you’re having twins or more. Multiple scans are needed if you have any condition which contributes to high-risk pregnancy. It is also performed if you’ve had some problems in previous pregnancies.

1. Scans in the First Trimester

During the first trimester ultrasound is usually performed between 8 to 11 weeks. This ultrasound confirms the gestational age, position of the placenta, and presence of multiple pregnancies. It also checks the physical growth and development of the fetus. It also helps to know the status of the pregnancy if in case any bleeding is there.

2. Scans in the Second Trimester

During the second trimester ultrasound is usually performed between 18-20 weeks. This scan detects the growth of your fetus and ensures that all organs like the skull, spine, brain, heart, kidney, lungs are developing at a normal pace.

Ultrasound in the second trimester helps to detect neural tube defects, cardiac defects, any limb defect, and gastrointestinal malformations like gastroschisis and exomphalos.

3. Scans in the Third Trimester

During the third trimester ultrasound is often done after 30 weeks, mainly to confirm the position of your fetus and placenta. To check whether the placenta is lying normally or is lying abnormally close to the inside of the cervix a condition known as placenta previa.

Ultrasound in the third trimester is a must when the woman is having twins or multiple pregnancies or has a condition that may affect the baby’s growth, such as pre-eclampsia.

Other Important Diagnostic Tests During Pregnancy

Other Important Diagnostic Tests During Pregnancy

Some other important diagnostic tests during pregnancy are:

Glucose Tolerance Test(GTT):

A glucose tolerance test helps to diagnose gestational diabetes in pregnancy. For this test don’t eat or drink anything overnight.  The technician measures the level of sugar in your blood when you’ve been fasting. They will take your first blood sample. Then they will ask you to drink 75g of glucose drink.

The technician tests the blood one hour after drinking the glucose. If you have high blood sugar levels on a glucose tolerance test, you have gestational diabetes. This makes your pregnancy a high-risk pregnancy. Read more about Gestational Diabetes here

Non-Stress Test (NST)

Doctors perform NST weekly in your third trimester. Doctors prefer to do it throughout the last month of pregnancy if it is coming under high-risk pregnancies. This test monitors the baby’s heart rate and his moves. The technician straps the  fetal monitor across the mother’s abdomen for monitoring

Contraction Stress Test

Doctors perform CST in the third trimester for high-risk pregnancies. Here a fetal monitor measures the baby’s heart rate in response to contractions stimulated by oxytocin. This test helps to predict how well the baby will cope with the stress of labor.

Apart from all these diagnostic tests during pregnancy regular checkups are very important. A routine check-up in combination with diagnostic tests can help to keep you and your baby healthy.


Editorial Team,

With a rich experience in pregnancy and parenting, our team of experts create insightful, well-curated, and easy-to-read content for our to-be-parents and parents at all stages of parenting.Read more.

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